Sen. Bernie Sanders (I-Vt.), ranking Democrat on the Senate Budget Committee, speaks at a news conference to discuss “The Rebuild America Act” at the U.S. Capitol on Jan. 27, 2015. (Win Mcnamee/Getty Images)

For years, transportation experts have called for a massive investment to save a network of roads, bridges and transit systems that have fallen into disrepair. A bill introduced in the Senate on Tuesday would meet that need, providing $1 trillion over the next five years.

Given that elsewhere on Capitol Hill members are scrambling for funds to keep annual federal transportation spending just above about $50 billion, coming up with an additional $148 billion on top of that would seem problematic.

“For too many years, we’ve underfunded our nation’s physical infrastructure. We have to change that, and that’s what the Rebuild America Act is all about. We must modernize our infrastructure and create millions of new jobs that will put people back to work and help the economy,” said Sen. Bernard Sanders (I-Vt.), the ranking minority member of the Senate Budget Committee, who introduced the $1 trillion bill.

Sen. Barbara A. Mikulski (Md.), the ranking Democrat on the Appropriations Committee, is a co-sponsor.

“By making smart federal investments in our nation’s infrastructure, we can create jobs and opportunities today while strengthening our economy for tomorrow,” Mikulski said.

A wall separating pedestrian and vehicle traffic crumbles from wear and tear on the aging Frederick Douglass bridge, an example of the national problem of poor maintenance and failing infrastructure, shown on Dec. 12, 2012, in Washington, D.C. (Nikki Kahn/The Washington Post)

The American Society of Civil Engineers (ASCE) has calculated that an additional $1.6 trillion should be spent on infrastructure by 2020. A 2010 report by the University of Virginia’s Miller Center of Public Affairs estimated that an additional $134 billion to $262 billion must be spent every year through 2035 to rebuild and improve roads, rail systems and air transportation.

“Senator Sanders’ initiative to invest $1 trillion over five years through his Rebuild America Act will have a far-reaching impact on restoring and modernizing our nation’s aging infrastructure,” said Casey Dinges, senior managing director at the ASCE.

Sanders, who did not specify a source of funding, said targeted investments would be made in roads, bridges, transit, rail lines, water systems, ports and inland waterways, national parks, municipal broadband systems, and the electric grid.

“My legislation puts 13 million people to work repairing the backlog of infrastructure projects all across this country,” Sanders said. “These projects require equipment, supplies and services, and the hard-earned salaries from these jobs will be spent in countless restaurants, shops and other local businesses. It’s no surprise that groups across the political spectrum — from organized labor to the U.S. Chamber of Commerce — agree that investing in infrastructure will pay dividends for future generations.”

The AFL-CIO’s Tom Trotter said, “This proposal provides a stark blueprint of what needs to be accomplished and provides an opportunity to create millions of new jobs.”